Use the most advanced color tool app of the market, recognize colors from images and browse the full list of the RAL and PANTONE colors with code and description. At the moment this app is the best color detector available for Android. This is the only tool that has the ability to calibrate the screen to have the maximum color fidelity as possible.
The application doesn't substitute the hardcopies of the RAL and PANTONE colors, but is only for support purpose.